Rolling mill for rings



April 28, 1953 F. s. SALTER 2,636,406

ROLLING MILL FOR RINGS INVENTQR. FRANK S/ZM/E Y JALTfR April 28, 1953 F.s. SALTER ROLLING MILL FOR RINGS 2 SHEETS-SHEET 2 Filed Feb. 28, 1951INVENTOR. TRIM/If SAD/7E) 5/1 LTfR Patented Apr. 28, 1953 ROLLING MILLFOR RINGS Frank Sidney Salter, Parkstone, Poole, England, assignor toThe Loewy Engineering Company Limited, London, England, a corporation ofGreat Britain Application February 28, 1951, Serial No. 213,211

- i In Great Britain March 30, 1950 Claims.

- The invention relates to ring rolling mills in which thewall thicknessof annular blanks is reduced and their diameter thereby increased by thecombined action of an outer and an inner working roll. Mills of thistype are frequently provided with means for guiding the blank during therolling operation. These means usually comprise rolls which are causedto engage a blank under hydraulic or other pressure, and which have tobe gradually retracted as the blank expands during the rollingoperation.

' Control of the receding movement of these guide rolls has so far beenefiected by hand and requires the constant and close attention of anoperator.

It is one of the primary objects of the present invention to provide aring rolling mill of the type described, in which the receding movementof the blank-guiding means during the rolling operation is automaticallycontrolled so as to relieve the operator of his task of supervising themovement of the guiding means.

, The invention relates in particular to ring rolling mills in which theguiding means are held in engagement with a blank by hydraulic pressurmeans, and it is characterised in the first place by the provision ofmeans for automatically controlling the hydraulic pressure means inresponse to the expansion of a blank, in such a way that the guide meansare caused to recede at the same rate as the expansion of the blankprogresses.

According to'a further feature'of the invention, the aforesaid automaticcontrol means comprise a relief valve for the pressure fluid in saidhydraulic pressure means, said relief valve being opened in response tothe expansion of a blank, whereby the recession of the guide means isefiected and closed in response to the recession of the guide means uponrelease of the pressure fluid by the relief valve.

The relief valve and its automatic control means may be incorporated ina hydraulic pressure system having additional and selectively operablecircuits for advancing or withdrawing the guide means without the reliefvalve becoming operative.

Further features of the invention will become apparent from thefollowing specification, in which two embodiments of the invention aredescribed by way, of example, with reference to the accompanyingdrawings Fig. 1 is a diagrammatic plan view, partly in section, of aring rolling mill according to the invention, showing only those partsof themill which are essential to the understanding of the invention.

Fig. 2 is a similar view of another embodiment of the mill according tothe invention.

Fig. 3 is a section through a valve forming part of the embodimentaccording to Fig. 2.

. In Fig. 1, i0 is an outer and Il an inner working roll of stringrolling mill, both of which are adapted to act simultaneously on theoutside and insiderespectively of a blank B, so as to reduce its wallthickness and thereby increase its diameter. One or both of the rollsIll and H are power-driven, and both rolls are constantly urged towardseach other by separate pressure means, whereby the required rollingpressure i produced. The mean for driving the roll or rolls and thepressure means are not shown or described here, as they are not part ofthe present invention.

Means are provided, comprising rolls l3 and M, to guide a blank B duringthe rolling operation through the pass formed by the rolls in and H. Therolls [3 and I4 are mounted on short axles [5 which are not driven andare connected by means presently to be described to a pin It on a ram11.

Ram I! is movable in a hydraulic cylinder l 8 in a direction whichcauses both rolls I3 and I4 to approach the blank B and to make contactwith its circumference. For movement of the rolls l3 and M in theopposite direction, ram I1 is hollow at one end, so as to form there ahydraulic return cylinder l9, which co-operates with a stationar ram 20.

The connection between the rolls I3 and M respectively and the pin Itcomprises pairs of oppositely arranged links 2| and bell-cranks 22,joined together by pins 2|. The bell-cranks 22 have pivot pins 22, andcarry at their free ends the axles l5 on which the rolls [3 and It aremounted. The free arm of the bell-crank for roll I3 consists of twoseparate sections 22! and 222, hinged together at 23, while the free armof the bell-crank for roll it is in one piece. Section 22I is formedwith a boss 24 on to which a relief valve 25 for the release of pressurefluid from cylinder I8 is mounted. The valve has a closure member 26which is normally held against a seat 21 by a spring 28, but can belifted from the seat 21 by an actuating rod 29. The latter is normallyheld apart from member 26 by a spring 30 which is stronger than spring28. Rod 29 has, further, a collar 3i which is normally held by spring 30in engagement with a flange on bell-crank section 22 I. Bellrcranksection-222 has also a flange which causes rod 219; tobe displacedagainst the action of spring 39, and thereby to lift closure member 2'6from its seat 27, thus opening relief valve as soon as section 222 isswung away from the blank B following the expansion of the latter duringthe rolling operation.

Closing of valve 2'5 can be effected without moving rod 29 back into itsformer'position by the action of bell-crank section 225, which, whenmoved away from blank B, will cause valve seat 2! to approach closuremember 26. This move-- ment of section 22! takes place when the ram ITis displaced to the right in Fig. l by the outward. movement of roll [4,upon the release of pres-- sure fluid from cylinder 18.

Valve 25 has two ports 32 and 33 which, by means of flexible pipes 34and 35 respectively are, connected to the cylinder l8 and to an exhaustline 38. In the position of Fig. 1, valve 25 is closed and the ports 32and 33 have, therefore, no communication with each other. Ram H is thushydraulically locked against movement to the right in Fig. 1, but willbe caused to travel in that direction upon. the expansion of the blankB, whereby rolls it and H! are moved' aside and the" relief valve 25operated as describedbefore.

Relief valve 25 forms part of a hydraulic pressure system which includescircuits for supplying and discharging pressure fluid to and from thecylinders It and i9 respectively. These circults are controlled fromavalve blocs as connected to a pressure fluid supply line 37, an. exhaust line 35, a line 39 leading to cylinder 38, and a line 49 leadingto cylinder P3. The block 36 has a number of valves ii to it which areoperated by means of a levers? and rock shaft 4i in anonventionalmanner, the" different positions of lever 45, and thus of the valvescontrolled thereby, being apparent from the diagrammatic illustration ofFig. l. The block 36 comprises, furthermore, a pressure limiting valve48 and a suction valve 49, both in circuit with cylinder 1! 9.

Before starting operations, the rolls l3 and hi are moved aside, so thata blank B can be placed over the working roll H. The valve actuatinglever 46 is now moved into the close position, pressure water is therebysupplied to cylinder l8 and discharged from cylinder I9, so that ram I'Itravels to the left in Fig. 1 and causes rolls f3 and It to move towardsthe blank B. It will be noted here that the two rolls l3 and 14 are notentirely symmetrically positioned relative tothe centre line through theaxes: of the rolls f6 and H inasmuch as the roll I3 is slightly furtheraway from that line than the roll i4, so that there will be a smallclearance between roll [3 and blank B when the roll 14 touches theblank. After the roll 14 has made contact with the blank B, the lever tois moved into the automatic position, whereby all valves in block 36 areclosed, excepting valve is. Cylinder 18 is thus placed in communicationwith exhaust line 33 whenever the ports 32 and 33 are placed incommunication with each other by the opening of the relief valve 25 inthe afore-described manner.

The rolling operation proper is now carried out and the wall thicknessof the blank B gradually reduced by the combined action of the rolls l0and H, the diameter of the blank B increasing at the same rate as itswall thickness decreases. The clearance between roll l3 and blank Bpermits the latter to expand freely first and to shift towards that rollwhile being in pressure contact with roll l4 due to the action of thepressure fluid in cylinder [8. On further expansion, blank B contactsroll l3 and moves it aside, whereby valve 25 is opened as describedbefore, and pressure fluid is released from cylinder Hi. This enablesroll [4 to give way to the expanding blank, and at the same timedisplaces ram 11 to the right in Fig. 1 through the connection betweenroll [4 and ram H' by parts 2 1V and 22. Displacement, of ram ll causesvalve 25 to be closed again, as described before. Roll H! is thus lockedtemporarily in position again, and the spreading of the blank takesplacetowards roll l3 which is moved aside, opens valve 25 and releasespressure fluid from cylinder 18, thereby permitting roll 14 to give wayto the spreading blank, closing valve 25 again, and so on until theblank has been rolled to its desired thickness.

The movements. of .the rolls [3 and M which cffectthe opening andclosing of valve 25 are very small, and follow each other continuouslyand in quick succession. It will also be observed that the chieffunction of roll I3 during the rolling process proper is to. control theoperation of valve 25, without transmitting any appreciable pressure tothe blank B, the. guiding action being; applied mainly by'roll. l 4..

The suction valve 49 serves to establish come municaticn betweencylinder [9. and exhaustline I lever lt has been moved to stop, wherebyall valves in control block 36 are closed, and relief valve 2%: is putout of action. The rolls l3- and M are thereby locked in theirrespective positions and are both firmly held in contact with the blankduring the rounding-off passes.

After rolling has been terminated, the lever 48 is moved into the openposition. Valves 4!, 43 and Q5 are thereby opened and valves 42 and 44closed. Pressure fluid is thereby admitted to cylinder l9 and dischargedfrom cylinder Ill. The rolls [3 and Hi are thereby caused to swingopento make room for the removalv of the finished blank and for theinsertion of a fresh one.

Fig. 2 shows another embodiment. of a rin rolling mill acccording to theinvention, in which the same principle as in. the embodiment of Fig. lis used for automatically controlling the blankguiding means. The mill.according. to Fig. 2-

has outer and inner working. rolls 60 and BI respectively, correspondingto the rolls Ill and H of the embodiment of Fig. l, and, further, rollsE3 and G l corresponding to the rolls [-3 and. M.

site to that carrying roll 64 is a casing 74 of a.

relief valve 15 which has two ports 16 and 71 connected to cylinder H bya flexible pipe 18,

and to an exhaust line, not shown, by a flexible pipe "is respectively.Cylinder [3 is constantly connectedto. .a line 89, and alwayssuppliedwith; hydraulic pressure fluid. In view of the-greater;

area of cylinder 'H,'however, the ram 18' is normally urged towards theleft in Fig; 2.

Movement of the ram in the opposite direction is effected by placing theports 16 and 11 in communication with each other through openingrelief'valve l5 and thereby releasing pressure fluid fromrcylinder' H.The relief valve has the same function to fulfil as the relief valve ofFig; 1,-and is therefore similar to the latter in its essentialfeatures. It has a closure member 81 normally held against a seat 82 bya spring 83, but adapted to be lifted from the seat by an actuating rod84 (see Fig. 3). Rod 84 is connected by a link 85 to an S-shaped lever86 pivoted at its centre about a fixed pin 8'! situated in the centreline of the axes of the rolls 60 and 61, the S-shaped lever being inturn connected by a link 88 to lever 66. Inserted'between a nut 89 onrod 84 and a cover plate 98 of valve casing 14 is aspring 91' whichnormally keeps rod 84 out of engagement with closure member 8!.

It will be apparent from the foregoing, and from an inspection of Fig.2, that anyoutward movement of roll 64 will cause valve casing 74 to bedisplaced towards the left in Fig. 2 relative to rod 84, which remainsstationary at this stage, with closure member 8| following the movementof the casing 14 due to the action of spring 83. In this way, closuremember 8! is caused to abut against rod 84 and to be liftedfromits seat82, placing ports 16 and T1 in communication with each other, wherebypressure fluid is released from cylinder 1 1.

Without moving casing 14 back into it former position, relief valve 15can be closed by displacing rod 84 to the left in Fig. 2 and thusallowing closure member 81 to return to its seat 82 under the action ofspring 83. This is effected by the aforedescribed connection between rod84 and lever 66, whereby displacement of rod 84 to the left of Fig.2takes place when the lever 66 is rocked about its pivot pin 68 in aclockwise direction upon the release of pressure fluid from cylinder 1I.

Relief valve 15 forms part of a hydraulic pressure system which includescircuits forsupplying and discharging pressure flu d to and from thecylinder H. These circuits are controlled from .a valve block 92connected to a pressure fluid. supply line 93, and exhaust line 64 and aline 95'leading to cylinder II. The block 92 has valves 98 and 91 whichare operated by means of a lever98 and a rock-shaft 99 in a conventionalmanner, the different positions-of lever 98, and thus of the valvescontrolled there by, being apparent from the diagrammatic illustrationof Fig. 2.

The operation of the blank-guiding means of Fig. 2 is substantiallysimilar to that of the means shown in Fig. 1 which have been describedbefore.

Before starting operation, the rolls 63 and 64 are moved aside so that ablank B can be placed over the inner working roll 61. The actuatinglever 88 is then moved into the close position, whereby valve 96 isopened and valve 91 closed. Cylinder H is filled with pressure fluidfrom line 93, so that ram 16 can overcome the constant pressure incylinder 13 and is displaced to the left in Fig. 2, swinging lever 66about its pivot pin 68 in a counter-clockwise direction. At the sametime, lever 61 is rocked in a clockwise direction through theafore-described link and lever connection comprising the parts 85 to 88and through the action of spring 91 which moves casing 14 to the rightwhen rod 84 is moved to of the relief valve by an electrical control.

the right. Thus, both rolls 63 and 64 are caused to move towards theblank B.

In the same way as in Fig. 1, the two rolls 63 and 64 are not entirelysymmetrically positioned relative to the centre line of the axes of therolls 68 and 6 l, inasmuch as the roll 84 is slightly further away fromthat line than the roll 63, so that there will be a small clearancebetween roll 64 and blank B when the roll 63touches the blank. After therolls 63 and 64 have been so' far approached to the blank B that theroll 63 makes contact therewith, thelever 98 is moved into the stopposition whereby both valves 98 and 91 are closed and the supply ofpressure fluid t cylinder ll cut off.

. The rolling operation proper is now carried out, and the wallthickness of blank B gradually reduced by the combined action of therolls 60 and 6|, the diameter of the blank increasing at the same rateas its wall thickness decreases. The clearance between the roll 6-4 andblank B permits the latter to expand freely first and to shift towardsthat roll while being in pressure contact with roll 63, due to thehydraulic force exerted on ram 18. On further expansion, blank Bcontacts roll 64 and moves it aside, whereby lever 6! is moved in acounter-clockwise direction in Fig. 2. Valve 15 is then opened asdescribed before and pressure fluid released from cylinder 1|. Thisenables roll 6 3 to give way to the expanding blank, thereby swinginglever 66 in a clockwise direction and closing valve 15 through the'linkconnection B8. Roll 63 is thus locked temporarily in position again andthe spreading of the blank takes place towards roll 64 which is movedaside, opens valve 15 and releases pressure fluid from cylinder ll,thereby permitting roll 83 to give way further to the spreading blank,closing valve 15 again and so on, until the blank has bee rolled to itsdesired thickness.

Similar to the case of Fig. 1, the movements of the rolls 63 and 64which effect the opening and closing of the valve 14 are very small andfollow each other continuously and in quick succession. The chieffunction of roll 64 during the rolling process proper is to control theoperation of valve 15 without transmitting any appreciable pressure tothe blank B, the guiding action being applied mainlyby roll 63. y

After rolling has been terminated, the lever 98 is moved into the openposition. Valve 96 is thereby closed, and valve 9! opened,- wherebypressure fluid is discharged from cylinder ll into line 94. This causestheram 78 to travel to the right in Fig. 2, whereby .both rolls and 64.are swung open to make room for the removal of the finished blank, andfor the insertion of a fresh one.

It is to be understood that the invention is capable of otherembodiments than those shown and described here. It is, for instance,within the scope of the invention to substitute the mechanical controlof the opening and closing movements In this case, the relief Valve 25or 15 could be arranged at a point distant from the mechanicalconnection between the hydraulic ram I! or 10 and the roll l3 and I4 or6-3 and 64 respectively and remain stationary, so that flexible pipesfor the supply and discharge of pressure fluid would no longer berequired. The mechanical connection between the hydraulic ram 11 or 10and the rolls l3 and Hi or 63 and 64 respectively would be provided withelectrical contact means which would be opened and closed for energisingor denereis ns a solen id cont ollin the relief valve! the opening andclosing of the contact means being effected by means similar to thoseeffecting the opening and closing of the relief valve 25 and r spectivly n he em odiments olescribed before.

What I claim is; 1. A, ri ro mill hav n an inner d an. outerworking rolladapted to reduce. the-wall thickness of annular blanks while allowingthe blanks to increase. in diameter at, the sa e time, guide rollsadapted to engage the outer periphery of a. blank during a, rollingoperation, a hydraulic cylinder and ram unit for moving said guide rollsinto engagement with a blank, automatically op-.

crated control means for alternatively reducing and re-establishing inquick succession the fluid pressure in said hydraulic cylinder whilesaid guide rolls are in contact with a blank, and means connected tosaid control means movable by change in diameter of said blank tooperate said control means.

' 2. A ring rolling mill having an inner and an outer Working rolladapted to reduce the wall thickness of annular blanks while allowingthe blanks to increase in diameter at the same time, guide rolls adaptedto engage the outer periphery of a blank during a rolling operation, ahydraulic cylinder and ram unit for moving, said guide rolls intoengagement with a blank, an automatically operated relief valve foralternately reducing and rte-establishing in quick succession the fluidpressure in said hydraulic cylinder while said guide rolls are incontact with a blank, and means operating said relief valve in responseto blank diameter change.

3. A ring rolling mill having an inner and an outer working roll adaptedto reduce th wall thickness of annular blanks while allowing the blanksto increase in diameter at the same time, guide rolls adapted to engagethe outer periphery of a blank during a rolling operation, a hydrauliccylinder and ram unit for moving said guide rolls into engagement with ablank, a resilient mechanical connection between said ram and one ofsaid guide rolls permitting a short displacement of one guide roll awayfrom the centre of a blank independently of the other guide roll, anautomatically operated relief valve for alternately reducing andre-establishing in quick succession the fluid pressure in said hydrauliccylinder while said guide rolls are in contact with a blank, andactuating means for opening said relief valve in response to adisplacement of said guide roll away from the. centre of a blank.

4.. A rin rollin mi l ha in n ne nd an outer working roll adapted toreduce the wall thickness of annular blanks while allowing the blanks toincrease in diameter at the same time, guide rails adapted to e age theout r er ph r of a. blan durin a ollin one a c a hydr c. cylinder andram unit for moving saidrguide rolls into engagement with a blank, aresilient me-.-' chanical connection between said ram and one of saidguide rolls permitting a short displacement of a guide roll away fromthe centre of a blank independently of the other guide roll, said connection comprising two elements pivoted to each other, and spring meansnormally urging one of said elements away from the other, anautomatically operated relief valve for alternately reducing andre-establishing in quick succession the fluid pressure in said hydrauliccylinder while said guide rolls are in contact with a blank, and aotuating means for opening said relief valve in re-. sponse to adisplacement of said guide roll away from the centre of a blank.

5. A ring rolling mill having an inner and an outer working roll adaptedto reduce the wall thickness of annular blanks while allowing the blanksto increase in diameter at the same time, a pair of guide rolls adaptedto engage the outer periphery of a blank during a rolling operation, ahydraulic cylinder and ram unit for moving said guide rolls intoengagement with a blank, a resilient mechanical connection between saidram and one of said guide rolls permitting a short displacement of aguide roll away from the centre of a blank independently of the otherguide roll, a rigid mechanical connection between the other of saidguide rolls and said ram, an automatically;

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 416,797 Munton Dec. 10, 1889 416,798 Munton v Dec. 10, 18,89

